Letters archive

My grandfather's favourite saying was "you cannot put an old head on young shoulders". Soon you might be able to, literally (28 February, p 10) . The wisdom of Alvin Toffler in his book Future Shock echoes from the past. We are being dragged into the future behind our technology, out of control and not …

Before we get carried away with the idea of head transplants, recall the article in the same issue about people who received bionic replacements for their hands (p 8) . Since we can make human-like robots, perhaps we should use the technique to transplant the head of someone with quadriplegia onto a robot body. It …

Apart from the technical difficulties of head transplants yet to be resolved, one of the ethical concerns would be whether or not the donor body was the same sex as the original. The implications are intriguing. Glasshouses, North Yorkshire, UK

Helen Thomson's article reminded me of the sci-fi classic That Hideous Strength by C. S. Lewis, in which a shady government research establishment is controlled by a reanimated severed head. Through this, Lewis addresses the question of what happens to the human soul when you separate the head from the body. Stroud, Gloucestershire, UK

There is an obvious problem with Google's plan to rank websites according to their trustworthiness (28 February, p 24) . Doing so by cross-referencing facts may be appropriate for current events, but perhaps not when applied to scientific facts. It is well known that scientific facts have a half-life, as existing research is superseded by …

Hal Hodson reports that Google's software for ranking pages on their trustworthiness will make its judgement by drawing on a store of facts gathered from the internet. Isn't this circular logic? How would the Google system handle a statement such as "glass is a liquid"? On the internet, the notion that glass is a slow-moving …

I was intrigued by the report of a black hole with a mass 12 billion times that of the sun, which apparently existed 12.8 billion years ago (28 February, p 14) . I can understand how the researchers estimated its distance, and therefore age, from the stretching of light wavelengths. However, the estimation of size …

The researchers do indeed address this in their paper. If the black hole was lensed, you would expect to see multiple objects or some other imaging artefacts. However, microwave imagery suggests they are seeing a single object.

In his passionate case for genetic engineering, Michael Le Page suggests that the limiting factor in germ-line genetic engineering is mainly technological (14 February, p 26) . If only. The real obstacle is appropriate knowledge of the effects that even the simplest genetic manipulations have. So far, we are only good at restoring deleterious mutations. …

While reading Edward Archer's article about the link between maternal inactivity and childhood obesity (28 February, p 32) , I wondered if he and other researchers have considered the significance of the adenovirus AD 36. This was described in some detail in New Scientist around six years ago (17 October 2009, p 47) . At …

Your article about an autonomous shipboard firefighting robot built for the US navy (14 February, p 22) caught my attention, particularly because it is bipedal. This surprises me, since bipedal robots tend to be cumbersome and slow – not ideal for a rolling ship, especially in stormy conditions. Surely a robot using wheels or a …

While the researchers admit that balancing on unstable terrain is especially challenging for bipedal robots, the goal is to create a robot capable of working alongside sailors. Such a robot must therefore be designed to have similar agility to humans.

Paul Bowden says that he doesn't consider pink to be a fundamental colour (28 February, p 55) . In this respect he is perhaps more correct than he realises. "Pinked" refers to petals with a serrated edge. This is the reason that scissors used by dressmakers to produce a serrated effect in fabric are called …

Once again, New Scientist shows that it is greater than the sum of its parts by the juxtaposition of two otherwise unrelated articles. Writing about microbes in the human environment (7 February, p 38) , Andy Ridgway reports that the bacteria found on the seat of a chair are associated with the gut and vagina. …

Any attempt to reform the US Congress that requires the cooperation of Congress is unlikely to have much impact (14 February, p 22) . Deep reform requires a disruptive change from outside the control of the incumbents. What we really need is a political party – or more than one – that imposes strict controls …

Oh, the praiseworthy efforts of optimistic youth at the hackathon to fix the US Congress. Only when constituents give more money to Congress than lobbyists do will Congress be more responsive to them. Hamilton, New Zealand

Mike Paterson places the blame on greed rather than religion for our overstretching of the world's resources (21 February, p54) . But surely the doctrine of many religions to produce as many children as possible is the most basic form of greed. Every extra person produced will want the best life possible, and every parent …

Chris Ford writes that agnosticism is a more scientifically defensible position than the alternatives (28 February, p 55) . I agree that it is scientific evolutionary atheism that it untenable. How can a creature evolved to swing from trees and then survive in the savannah claim to have a brain capable of deciding on the …

I have been agnostic for as long as I can remember, and atheist for most of that time. I'm aware of the supposedly untenable position this puts me in, but I prefer the term a-theist: I am without god. Even if the ether is swirling with all the deities we have invented over the millennia, …

• The light-activated nano-therapy used by Adah Almutairi to treat macular degeneration was tested in animals, but not the human variety (28 February, p 31) . • In discussing assisted suicide, we wrote that Canada has legalised the practice (28 February, p13) . We should have said the Supreme Court has ruled that it should …